package Bite;

import java.util.Scanner;
import java.util.Stack;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        // 注意 hasNext 和 hasNextLine 的区别
        while (in.hasNext()) { // 注意 while 处理多个 case
            Stack<Character> stack = new Stack<>();
            String s = in.next();
            for (int i = 0; i < s.length(); i++) {
                if ( !stack.isEmpty() && stack.peek() == s.charAt(i)){
                    stack.pop();
                }else {
                    stack.push(s.charAt(i));
                }
            }
            StringBuilder stringBuilder = new StringBuilder();
            while (!stack.isEmpty()){
                stringBuilder.insert(0,stack.pop());
            }
            if (stringBuilder.length() == 0){
                System.out.println(0);
            }else {
                System.out.println(stringBuilder);
            }
        }
    }
}
